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selectools: Hook for Claude Code

.claude/settings.json

SessionStart is a hook for Claude Code from johnnichev/selectools. Its token cost is not measured, scanned A, original, Apache-2.0.

A session-start hook that runs a shell check when a coding session begins. It looks for old CLAUDE.md or AGENTS.md instruction files.

In plain words
What is it for?
Use it to detect stale project instructions and display a warning at session startup.
Why use it?
It warns when those files have not been reviewed for more than 14 days and may no longer match the project.

Hook for Claude Code

Written for Claude Code: SessionStart hook event. Also seen: mentions CLAUDE.md; mentions AGENTS.md.

This is johnnichev/selectools's own configuration. It tells Claude Code how to work on selectools itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything selectools configures →

One of 5 entries in settings.json upstream. Installing this one merges just its entry into your config; the other 4 are separate, each on its own page.

not rated 11repo 4d ago A scan tokens not measured original Apache-2.0
View source ↗ johnnichev/selectools selectools.dev
Reuse

Borrowing it

Nothing to install: this file belongs to johnnichev/selectools. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/johnnichev/selectools/main/.claude/settings.json
Clone the repo
git clone --depth 1 https://github.com/johnnichev/selectools

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for SessionStart

README.md
[![agentmods](https://agentmods.dev/badge/hooks/johnnichev/selectools/session-start/github.svg)](https://agentmods.dev/hooks/johnnichev/selectools/session-start)
Your own site
<a href="https://agentmods.dev/hooks/johnnichev/selectools/session-start"><img src="https://agentmods.dev/badge/hooks/johnnichev/selectools/session-start/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for SessionStart

Your own site · 80×15
<a href="https://agentmods.dev/hooks/johnnichev/selectools/session-start"><img src="https://agentmods.dev/badge/hooks/johnnichev/selectools/session-start.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session not measured What this adds to a session before it is invoked.
When invoked not measured Not applicable: nothing here is loaded into a session.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Security

Grade A, and why

SessionStart scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.

A static scan of the commands this hook runs, not an audit. A hook is shell that executes on your machine at the event it names, which is why every command in it is printed with what was found.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude/settings.json · 13 lines

What it actually says

{
  "SessionStart": [
    {
      "hooks": [
        {
          "type": "command",
          "command": "python3 -c \"import os,time,json; stale=[f for f in ['CLAUDE.md','AGENTS.md'] if os.path.exists(f) and time.time()-os.path.getmtime(f)>14*86400]; msg='\\n'.join(f'Warning: {f} is over 14 days old — review for staleness' for f in stale); print(json.dumps({'systemMessage':msg}) if msg else '{}')\"",
          "timeout": 5
        }
      ]
    }
  ]
}
Same file

What else settings.json configures

This page is one entry in a file that holds 5. Installing the file brings all of them; each is measured and scanned on its own page.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2mo ago First seen · 13 lines scan A cd8ad50841b7

Subscribe to this mod's changes

SessionStart is a hook published in the GitHub repository johnnichev/selectools (11 stars, last pushed 4d ago), licensed Apache-2.0. Its token cost is not measured: a hook is shell that never enters the context. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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Related

SessionStart compared with hooks from other repositories

SessionStart next to 6 hooks from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
SessionStartjohnnichev/selectoolsHook114d agoApache-2.0A—Claude Code
PostToolUsesupabase/supabaseHook115kyesterdayApache-2.0A—Claude Code
SessionStartsupabase/supabaseHook115kyesterdayApache-2.0A—Claude Code
SessionStartgoogle-gemini/gemini-cliHook109kyesterdayApache-2.0A—Claude Code
PreToolUseapache/supersetHook75kyesterdayApache-2.0A—Claude Code
PreToolUseanthropics/claude-cookbooksHook54k2d agoMITA—Claude Code
PostToolUseanthropics/claude-plugins-officialHook46kyesterdayApache-2.0A—Claude Code